Bomb fuze



1957 G. ROBERTS ET AL BOMB FUZE 6 Sheets-Sheet 1 Filed Jan. 51. 1952 INVENORS GEORGE ROBERT 5 JMES E. BEV/NS Jan. 22, 1957 Filed Jan. 51. 1952 FIG. 2

G. I. ROBERTS ET AL BOMB FUZE 6 Sheets-Sheet 2 INVENTORS GEORGE (ROBERTS JAMES E. BEV/NS Jan. 22, 1957 INVENTRS GEORGE ROBERTS JAME5 E. 6EV/NS 0 J? M Jan. 22, 1957 G. ROBERTS ETAL 2,778,311

BOMB FUZE Filed Jan. 31. 1952 6 Sheets-Sheet 5 uoa F|G 7 INVENTOR5 GEORGE [ROBERTS JAME5 E. BEV/NS BVC.R.W

Jan. 22, 1957 G. 1. ROBERTS ETAL BOMB FUZE 6 Sheets-Sheet 6 Filed Jan. 51. 1952 FIG. 9 FIG. 10 FIG. H

FIG.

INVENTORJ GEORGE ROBERTS U d tates Patent 2,778,311 BON-FUZE Application January.3l, 1952,:Sefia1269,206

10Clafims. (Cl. 102-411 ThS invention relates to aerial bombs and more particularly t bomb fuzes which are used in combination With aerial bombs t0 affect arming and functioningthereof=under predetermined conditions.

-'In the construction of the above type of bomb fuzes, precations must be taken to incorporate allof the -safety features possible in the design of the fuzes. Since the bombs are to be released from aircraft in flight, the fuzes must be set to operate at a safe distance from the craft. A fter the bomb-leaves the craft, a predetermined time interval must elapse before it is expl0ded so that the craft and occupants therein are not injured by the explosion.' .IJieans are usually provided to arm the fuze, that is, p npare the fuze for functioning, after which, pressure Sensitive means become operative to cause the fuZe to' function when it -attains a preset altitude.

'I he present invention, therefore, contemplates abarometric bomb fuze Which incorporates a maximum number of. safety eatures -to protect the user thereof from injury. Novel means are provided to arin the fuze after-a predetermined distance of air travel together With means 'for efEecting functioning of the fuze at a preset altitude; A toggle arrangement comprising a pair of trip pins employed incombination with a firingpin and aresilent spring means is provided to relieve the load on a tripping mechanisin which is actuatedby a pressure sensitive member. Novel cover means areemployed which prevent v actuaonof the arming mechanism before thefuze is reieased' from craft in fiight. --When the bomb,- together With the fuze, are dropped from the craft, novel means remove the cover means so -that the fuze marine armed and the rby caused tOfunction under conditions manually presetbefore the bomb is released.

An object of the present invention, therefore, is -to provide an improved bomb fuze whichdncorpomtes a maximum number of safety' features to prevent injuryto, the user.

Another object is to provide a-barometfic .bombfuze Wherein novel means are provided :to seal the various. components of the fuze from :surrunding environmetital conditions.

A further objeet is to provide an improved barometric bomb fuze wherein novei airtravelmeans may be initially preset t0 :armthe fuze, after =azpredetermined air ;travel.

Still another object is to providean improved :barometic bomb fuze wherein a novel barometrc systeni is arranged to release a 'fiiing pin tfipping arrangement Which causes the 'fuze to fnnction ata predet ermiried altitude. 4 7

A. still further object is to provide an improved baro metric bomb fuze wherein a novel toggle arrangement and spring.meas impose as little loadas possible On. the barometric pressure sensinglmeans whicheflects .firirig,of the fpze.at a-predeterminedgltitude.

.Ihe;above and other objects and advant ages 9f,th present,invenon .will appear more fullwhe jnafter {from a considerafionr of n the ;detailed r-descriptio yvinflch f.9l lows Batented Jan. 22 1957 g 2 taken together with the aceompanying drawings wherein one embodimentof the invention -is iliustrated.

:In the drawings, whereiri like reference characters refer to likeparts throughout the s'everal views;

Fig. 1 is a top plan vieW-of'the exterior of the bomb fuze embodying the presentinventon; 7

Fig. 2 is a side elevational view, in section, of the fuze of Fig. 1;

Fig. 3 is a rear view of the air travel assembly and showing in particular an opening in a rotatable plate which is adapted to cooperate with a release rod for arming the fuze;

Fig. 4 is a diagrammafical representafion of the gear train forming part of the air travel assembly.

Fig. 5 is a sectional View of a sliding detonator arrangement for efiecting the functioning-or firing of a binb (mot shown) to be connected tothe fuze;

Fig. 6 is a top plan View of me pressure sensitive member or 'aneroid;

Fig. 7 isan elevational vievvof the barometric stting arrangement together with the fixing pintripping mechani sm;

Fig. 8 is a rear view of the firing pin tripping mechanism shownin Fig; 2;

Fig 9 is a side levaonal view of the trip lever reIease spring in full line and brokenline positions;

.'Figs. l0 and 11 are side views of the trip pins used in the noirci .toggle arrangement;

Fig. 12is aside view', in section, of 3. guide plate-used With the trip pins et Figs. and 11;

Fig. 13 is a cross-sectionl view of the firing pintogether With the trip pins et Figs. -10 and 11 and-the guide plate et Fig. 12{and Fig. 14 is a front eievationaivewof thefuze of Fig. 1 with a portion of the front cover broken away.

Referring now to the drawings for a more detailed description of the present invention and moreparticulafly t0 Fig. 1 wherein one embodiment thereof-is clearly illustrated, a barometric bomb'fuZe generaliydesigmated by the numrai 21is adapted for threaded engagement to the nose of-a bomb' (notshown) by means of a threaded portion 22. "Fuze 21 comprises a cylindrical-housing 24 which accommodates an air .travei-setting screw*25 having one end flush With the outside surface ofthe housing and the opposite end extending through the wallofthe housing. Theopposite-end of -screw 25 has formed'thereon a gear tooth 26Which engages a toothed portion-or gear 28 -formed on a circular member 29 (Figs. 1 and 2) which carries on the periphery-therecf adial 31'viewable through a window 32cementedin the housing. 'Dial 31 bears indicia caiibrated inthousands of feet of air travel and isread Wh r espect to an index 33 out in window 32. Positioned inside of circular member 29 andheld therein by a retainer ring 35 is a dise orplate 36 which has formed therein an opening 37 (Fig. 3).

Opening 37 bears a predetermined relationship to the indici on dial3l insofar as the angular dispiacemenbof the opening' from a reference position designated -as R. {P. (shown in brokenlincs in Fig. 3) may-be read on diai 31 as .50 t1;any=thousands of feet. "From the f0regoing, it is apparent tht rotation:ofset tingscrew' 25 will efreet-anguiar dispiacement of dial "31 and plate 36-to ahgulariy displace opening 37 a predeterminednumber ofdegrees whichcorrespond -tofeet of air travel. The

3 2.5, comprises an air driven vane (Fig. 2) located in a ch-amber 41 formed in housing 24. Formed in the nose of the fuze and leadixig to bhamber 41 is an air entry port 42 which permits air to enter the chamber. An exhaust duct 44 located in chamber 41 and formed by an open bell-shaped member 45 and a member 46 together with a pair of elongated exhaust ports 43, formed in housing 24, permit air entering the chamber to be exhausted therefrom. Vane 40 is positioned within bellshaped member 45, and in the path of the air flow, to be driven by the passage of air, thereby effecting rotation et a shaft 49 upon which it is mounted. Shaft 49 is journalled for rotation in bearings retained in plate36 and in a supporting member 50, and has a pinion 51 formed at the opposite end which'drives a gear train generally designated by numeral 52.

The arrangement of gears forming gear train 52 is diagrammatically shown in Fig. 4 Wherein the shafts supporting the various gears are numbered according to their sequence et operation. Vaneshaft 49, is designated, in this latter figure, by the numeral 1 for purposes of clarity. The shafts supporting'the gears of gear train 52 are journalled in plate 36 and supporting member 50. The gear supported on shaft 7 is the output gear of the gear train and is adapted to mesh with an internal gear 53 formed on the inside of circular member 29. It may be seen that rotation et vane 40 efiects rotation of plate 36 and supporting member since circular member 29is locked by screw 25 and the output gear of gear train 52 creeps on internal gear 53.- Gear train 52 has a 12,000-1 gear ratio and, therefore, the rate of speed of the plate Wil be very small compared to the rate of speed of vane 40.

Sealing chamber 41 from a second chamber 55 formed in housing 24 is a plate or wall 56 and a gasket 57 (Fig. 2). An air travel release rod 53 is substantially located in chamber 55 and has reduced diameter portions 59 and 59A, the latter being biased against plate 36 in chamber 41 by a spring 60. The end of portion 59A is positioned in the reference position R. P. and in the path of travel of opening 37 so that When the two are aligned with respect to each other, portion 59A is urged into the opening under tension of spring 60. The opposite end of rod 58 projects through a rib wall portion 61 of a ring casing 62 secured to housing 24 by screws 63, one being shown in Fig. 2. Rod 58 supports a detonator. 65 resiliently biased against the rod by a spring 66 which is held in po- I U I l I member 29. Stops 35 and 86A project outwardly from toothed portion 28 and are adapted to engage gear tooth 26 of screw 25 when it is attempted to rotate dial 31 below the five hundred foot indication and beyond the twenty thousand foot indication, respectively. Thus, if screw 25 is adjusted t0 rotate d-ial 31 to read below five hundred feet, stop 86 will engage the screw to prevent rotation of the dial in that direction. If the screw is adjusted so that dial 31 will read above twenty thonsand feet then stop 86A engages screw 25 to prevent further rotation. in this manner, alignment of rod 58 with opening 37 in plate 36 is prevented, whereby the possibility of premature arming of the fuze manually, by adjustment of screw 25, is eliminated.

Fuze 21 is adapted to be armed within a range of 500 10 20,000 feet of air travel after being released from a craft in flignt. If it is desired to arm the fuze after 10,000 feet of air travel, screw 25 is adjusted until the numeral 10 on dial 31 coincides with index 33. As set forth hereinbefore, rotation et screw 25 eiects rotation of circular member 29 and plate 36 to angularly displace opening 37, and in this assumption, the opening will have been displaced 150 degrees from the reference position. When the bomb is released from the craft, air driven vane 40 is rotated to angularly displace plate 36 and opening 37 in an opposite direction while circular member 29 is maintained locked. After 10,000 foot et air travel the opening will be aligned with end portion 59A et air travel release rod 58 so that it will be moved into the opening by spring 60. As rod 58 moves to the left (Fig. 2) and out of ring casing 62, detonator 65 is forced downwardly by spring 66 Whereby explosive charge 69 becomes aligned with openings 70 and 81. The fuze is now in an armed condition.

Fuze 21 embodies altitude setting means generally des ignated by the numeral 87 (Fig. 7) for presetting the altitude at which the fuze is to function to detonate the bomb. Altitude setting means 87 comprises a slotted and resiliently nrged member 88 (Fig. 7) which extends from chamber 55 into an opening 89 formed in the housing. The end of member 88 within the housing has a slot ont therein to accommodate a pin 90 secured to a threaded member 92 which is rotatable but restrained from moving axially. Member 92 is supported by a bracket 94 and has a pair of separated threaded portions 96 and 97. Threaded portion 96 cooperates with a forming the aneroidfare mintined inoperafive until reIeased for functioning so that unnecessary movement of the capsules and detent lever is prevente d.

Arranged underneath cvers 160 and 162, and in diametrically opposed groov=es 164 (one shown in.Fig. 1) formed in the exterior of housing 24, is an armingspring wire 165, under tension, which extends around the nase or front of the fuze. Tireends of wire 165 are bcnt to engage a second arming spring wire167 which encircles the housing andis arranged transvrsely thereof. The ends 168 and 169 (Fig. 14) oflwire 167 are turned upwardly at right angles to the wire and are brought together under tension. T0 maintain ends 168 and 169 together, a lug 170 is soldeted to end 168 and a cotter pin 171 is inserted'into an opening 172- formed in the lug, whereby the cotter pin prvents the ends springing away from cash o'ther. Arming wire 165 runs past air entry port 42, underneah'cover 16Z,and is positioned in a slot fonned in one end f a vane rotor stop 173 (Figs. i, 2 and 14) which is slidable in a fixed guide vane 175 (Fig. 2) in the port. Vane rotor stop173 is normaily biased to left, as seen in Fig. 2, by a helicnl spring 177 which is positioned in a eut-out formed in the guide Vane. The opposite end of the vane rotor stop has a tongue connection 179 adapted for projection into a Slot cut in the adjacent and of air drivei1 shaft 49-: When arming Wire 165 is assembled to the fuz,.the wire engages vane rotor stop 173 and moVes it against the tension of spring 177 until tongue 179 projects into the,slot of air driven Vane shaft 49. From the fOregoing, it is readily apparent that air driven vane 11) cannot ce rotated When wite 165 engages the 3101: ont in stop .173.

The above arrangement defines a novel cover removing means whicn remo'ves covers 169 and 162 when the aerial bomb (net shdwn) and fuze21 arc dropped from :aircraft in ight. Cover 160 is madeof a thin sheet of plastic material which may be readily tornor destroyed and is out slightly at two rearWardly points where it makes contact With arming wire165. Wheri the bomb- (net shown) is mounted on the craft, a wire (not shoWn) is passed through a second opening 180 inlug 1711 directly r below the opening 172 (Fig.'l4), and afterwards cotter pin 171 is removed. The Wirein opening 1811 is fixed t0 a oomb releasing mechanism (net shown) whic'h, Whenactuated, allows the bomb to fall frein the craft but retains the wire, whereby the latter slipsout of opening 1S9. At this point, ends 168and169 of wire 167 spring apart and reiease the turned ends of wire'1fi7 Whichivere also previously under tension. Wire 165, thus springs outwardly from the fuze, ripping or tearing plastic cover 160 and removing cover 162 at the same time. Varie rotor stop 173, which was biased against spring 177, is now urged to the left by the latter t0 disengage Longue connection 179 froni the siot formed in air driven vane shaft 49. With the removal of covers 1611 and 162 and the arming wires, vane 40 is now free to rotate by the passage of air through the entry port and exhaust ports t0 actuate the air travel rnechansm for arrning the fuze. Removal of cover 1611 also exposes static pressure orifices 150 to ambient pressures whefeby the latter are conimunirated to aneroid 119 to efEect functidning of the fuze at the preset altitude. Besidesproviding the means for removing envers 1fi( and 162, it is apparent that arming wires 165 and 167 also directly prevent actuation of the air travel mechanism until the bomb i dropped from the craft.

From the friregoing, it is apparent that the present invention providesnovel means for arming a bomb fuze after a predetermined nurnber of feet of'air travel together With means for releasing a fixing pin to efiect funetioning of the fuze at apres'et altitude. Furthermore, the utilization of a toggie arrangement in combination with the firing pin efiects a decrease in the load borne by the tripping mchanism{ 1t may be readiiy seen that the present invention, by incorporafing the cover means and arming wire arrangement, provides for maximum accuracy and safety in the use of aerial bombs employing the novl subject barometric bomb fuze.

Aithough one embodiment of the invention has been illustrated and described in detail, it is to be expressiy understood that the invention is not limited thereto.

Various changes can be made in the design and arrange ment of the parts without departing from the spirit and scope of the invention as the same Will now be under stood by those skilled in the art.

We claim:

1. The combination comprising a bomb fuze mechanism, a casing for said mechanism, a chamber formed in said casing, pressure sensirig means mounted in said chamber and connected to eiect functioning of the bomb fuze mechanism When the pressure in said chamber attains a predetermined value, static pressure orifices formed in said casing and communicating With said chamber, means comprising a destructibie cover on said casing covering said static pressure orifices to sea1 said barometric sensing means to foreign matter and to ambiant pressures exterior the casing, spring means positioned between said cover and said casing and adapted to destroy said cover, and detachable holding means for biasing said spring means toward said casing, said holding means being adapted to release said spring means, when detached, whereby the latter destroys the cover to expose said static pressure orifices to ambient pressures exterior the casing.

2. The combination comprising a bomb fuze meching and under said cover extending transversely of said first member, said second member having the ends thereof held to the casing by said first member, the ends of said second mcmber, when released by detachment of said first member, being 'adapted to spring from the casing to effect destruction of said cover to expose the static pressure orifices to ambient pressures exterior the casing.

3. An aerial bomb fuze assembly comprising a bomb fuze mechanism, a casing for said mechanism, a chamber formed in said casing, air flow responsive means positi0ned in said chamber and connected to arm the fuze after a predetermined distance of, aerial travei by the bomb fuze assembly, said air flow responsive means actuated by passage et air through said chamber, air cntry and exhaust ports formed in said casing and com municating With said chamber to provide passage of air therethrough, a cap ou said casing sealing the entr port, a destructible cover encircling said casing and covering said exhaust ports, a resilient element on the casing positioned under said cap and said destructible cover, and

' detachable means on the casing and in contact with said resilient element for biasing the resilient element against the casing, said means upon being detached, serving to release said element whereby the latter destroys the cover and removes said cap to expose said entry and exhaust ports t0 permit the actuation of said air flow responsive means.

4. A bomb fuze assembly comprising a bomb ruze Formed in trip lever 123 and adjacent firing pin 75 is a rectangular slot 126. Bearing against lever 123 and below slot 126 is the projection 128 of a fiat trip lever release spring 129 which comprises a leg portion 130 and a foot portion 131 (Figs. 8 and 9), the latter directly secured to a stationary supportingbracket 133 by a pair of screws 134. The upper part of leg 130 has formed at right angles thereto 21 flange portion 135 which includes a substantially rectangular slot 136 located directly above projection 128 (Fig. 9). Leg 130 of spring 1292, when unrestrained, moves to the broken line position seen in Fig. 9 but when trip lever 123 .engages projection 128 the spring is brought to slid line position of Figs. 8 and 9.

The bottom side and right side of slot 136 engage a trip pin 138 (Figs. 8, 10 and 13) when trip spring 129 is engaged by trip lever 123, the spring holding the pin against a fiat side of firing pin75. One end of pin 138 engages an adjacent end of a second trip pin 139 (Figs. 11 and 13) which contacts a part of the fiat surface of firing pin 75 and a guide plate 141 (Figs. 12 and 13) secured by a screW 143 to a fixedly supported beafing block member 142.

Block member 142 has an opening therein through which the forward portion of firing pin 75 passes, and the block member -is dimpled so as to provide a bearing surface for the opposite end of trip pin 139. The opposite end of pin 138 similarly bears-against a dimpled surface in a washer 144 soldered to firing pin 75. The

adjacentends of the two trip pins are urged into engagement by a helical spring 146 (Fig. 8) which bears against one side of washer 144, the spring acting also to bias the firing pin for movement to a firing position. Trip pins 138 and 139 are arranged so that their contacting ends are position d slightly below the center line of the firing pin to -form in elect a toggle arrangement. In this manner, most, ifnt all, of the loadexerted by firing helical spring 146 is transmitted by the trip pins to fixed block member 142 with perhaps a very slight vertical load on flange portion 135 of trip spring 129 and a slight side load on guide member 141. The reason for this toggle arrangement will be brought outpresently in the description of the operation of the tripping mechanism which releases firing pin 75 to affect functioning of the fuze.

As was mentioned previously, altitude setting means 87 is provided for presetting the altitude at.which the fuze is to function. Assuming a condition wherein it is desired to efiect functioning of the fuze at an altitude of 5000 feet above a barometric pressure of 30 inches of mercury, a tool is inserted in the slot provided in mem ber 88 and turned until the graduation indicating the numeral on dial 102 is brought into coincidence'with the graduation indicating the numeral 30 on barometric pressure dial 105. Rotation of threaded member 92 will pro-duce movement of slidable member 1419 on track member 108 to pivot detent member 114- about the bimetal fulcrum 115 to adjust the point of contact between the last two elements so as to adjust the trip ofi point of the tripping mechanism. In practice, the fuze is preset for the predetermined functioning altitude before fiight so that the pressure in barometric chamber 55 at the time of presetting corresponds to ground level altitude. The

eroid 119 with changes in altitude.

6 In,this ,manner, thefipositon cf .dete,ntflrnember ll4 may be freely adjusted Wi thbut,releasing the trip lever.

Static pressure.orifices,l5fl are formed in housing 24 (Fig. -1) and communicate chamber to ambient pressures exterior thereof so as to var the pressure on an- Compensation of aneroid 119,for satisfctory operation of the fuze over a specified temperature range is accomplished by the bi metal str-ip comprising rod 115. The range is adjusted by Varying the position of rod 115 on the straight section of detent 114. When the fuze is dropped from aircraft in flight, rod 115 may or may not be in contact With dotent 114 because the pressure at the releasing altitude is less than the pressure at ground level so that aneroid 119 will have expanded. Lip 121, however, will engage shoulder 122 because detent'1l4 is biased toward trip lever 123 by a spring 151 positioned on pin shaft 112 and in engagement with the upper portion of the detent member. A stop 151A (Fig. 7) is provided to limit theex pansion and overtravel of the aneroid.

As the fuze descends to a lower altitude, and after;the

preset numberof feet of air travel, the fuze becomes armed, as described h(ereinbefore, and rod 58 moves to an,armed position th-ereby pulling shoulder 143 out et contact with trip lever 123. At this point, detent 114 works against spring. 125 tomaintain the trip lever in a firing pin blocking position (Fig. 7). As the fuze reaches and passes the preset functioning altitude, rod 115, which has been moving to the left with the Contracting aneroid, functions as a tripping pin to contact and pivot detent 114 thereby disengaging lip 121 'from shoulder 122 to release trip lever 123 for counterclockwise movement by spring.125. The bottom ;of trip lever 123 being disengaged from shoulder 148 on rod 58 clears the rod and allows movement of the lever. As the trip lever moves, projection 128 of spring 129 falls into rectangular slot. 126 of the trip lever Under its own spring tension to thereby release trip pins 138 and 139 which toggle in a vertical direction, toward rod 58, to permit firing of firing pin 75 under the tension of helicalspring 146. The forward end of firing pin 75 penetrates diaphragm 72 in opening 78 to explode charge 69, now aligned With the opening,thereby detonating-the bomb (mot shown). It will now be apparont that.the toggle, arrangement of trip pins 138 and 139 provides for a very slight load on the tripping mechanism. This is important because it relieves the load.on aneroid 119 so that the latt&ermay operate eficiently and accurately in-actuating the tripping mechanism to eifect functioningof the fuze at the-predetermined altitude.

Means are provided to protect the interior of housing -trom prevalent weather conditions, such as rain, snow and -dust, and other foieign matter; and to prevent ambierit pressures eXterior the housing from afiecting aneroid 119 until the fuze is released from aircraft in flight.

Oftentimes betore.the loading of aerial bombs in aircraft, the .fuzes may be .exposed to water, freezing temperaturcs and/or mud which would clog the static pressure orifices and the air entry and exhaust ports. A transparpressure in the chamber therefore, will have contracted aneroid 119 to a position otherthan that shown in Fig. 7 and lip 121 of detent 114 will not be in engagement With shoulder 122 of trip lever 123. As will be seen prcsently, rod 115 serves. as a fulcrum when the pressure Vent downward 1novementof the trip lever by=spring 125.

entplastic cover 160, theretore, .is provided on the exteriobof housing24 and over orifices 15) to seal-the various components inbarometric chamber 55 front the atmosphere (Fig, 1.). Cover 3160 also seals exhaust ports 48 .to protect the exhaust ducts 44 in chamber 41. One end of cover 1613 overlies the flanged portion of a lightweight metallic cover 162 which.fits over the nose of the fuze to seal air entry port 42. A transparent coat of lacquer issprayed on cover 1663 to form a substantially air tightseal for the fu'ze. In this manner, the fuze may be subjected to any environmental condition and still be operative for functioning when required. Transparent cover 16.serves also to prcvent changes in ambient pressures exterior the housing .from communicating with chamber 55 to expand and.contractanemid 119 while the vcraft maybe operating at.diterent altitudes. ln,baro- :metrie bombfuzes,it is usually required that the capsules air ,therethrough, and removable cover means on said casing and covering said orifices and said ports whereby said cover means permit functioning of the fuze when removed and prevent functioning thereof when retained.

5. An aerial bomb fuze assembly adapted for use with bombs dropped from aircraft, comprising a bomb fuze mechanism, a casing for said mechansim, a chamber formed in said casing, air entry and exhaust ports formed in said casing communicating with said chambrer to provide 21 passage of air therethrough, removable cover means on said casing for sealing said ports, air flow responsive means positioned in said chamber and connected to arm the fuze after a predetermined distance of aerial travel by the bomb fuze assembly, said air flow responsive means including an air driven vane located in said chamber and responsive to flow of air through said chamber,

a stop member movable in two directions, said member when moved in one direction restraining vanemovement, and when moved in the other direction permitting free movement of the vane, anddetachahle resilent means on said casing pbsitioned under said cover means and in engagement with said stop member, said resilient means upon being attached to said casing urges said stop men ber in a direction to restrain movement of said vane, and said resilent means upon being detached eflects removal of said cover means and permits movementof said vane to efect actuation of: said air travel means.

6. A bomb fuze assembly for use with bombs dropped from aircraft, comprising a bomb fuze mechanism, means for arming said fuze mechanism after a predetermined number of feet of aerial travel by the bomb fuze assemb-ly, a slidable rod forming part ofsaid means and movab=le from an unarmed to an armed position when the fuze assembly has travelled the predetermined number of feet, a firing pin biased to move in une direction, means comprising a resiliently urged trip lever associated with said rod which maintains said firing pin in an inactive position when said rod is in an unarn1ed position, and to release said firing pin when said rod is in an armed position, detent means operatively associated with said trip lever for restraining the trip lever from releasing the firing pin when said rod is moved to an armed position, and pressure sensitive means for actuating said detent means to release said trip lever and said firing pin.

7. A barometric bomb fuze assembly for use with bombs dropped from aircrafi, oomprising a homb fuze mechanism, means for arming said fuze mechanism after a predetermined number of feet of aerial travel by the bomb fuze assembly, a slidable rod forming part of said means and movable from an unarmed to an armed position when the fuze assembly has travelled the predetermined number of feet, a raised stop formed on said rod, a firing pin biased to move in one direction, a pivotally mounted and resiliently urged trip lever contacting said stop when said rod is in an unarmed position and to clear said stop when said rod is in an armed position, said lever maintaining said firing pin in an inactive position when contacting said stop, and releasing said pin when clear of said stop, detent means operatively associated with said trip lever for restraining the trip lever from releasing the firing pin when the rod is moved 10 to an armed position, and pressure sensitive means for actuating said detent means to release said trip lever and said firing pin.

8. A barometric bomb fuze assembly adapted for func tionin at a predetermined altitude, comprising a firing pin biased for movement to a firing position, a pivoted detent member, a p-ivotally mounted lever engageable by said detent member for maintaining said pin in a non-firing position, means yieldably urging said lever to release said firing pin and acting in opposition to said detent member,

and pressure responsive means displaceable in response to variations in pressure to move said detent member out of engagement with said lever when a predetermined altitude is attained, whereby said yieldable means pivots said lever to release said pin to a firing position.

9. A bar0metric bomb fuze assembly adapted for funetioning at a predeterminedaltitude, comprising a firing pin biased for movenient to a firing position, a pivoted detent member, a pivotally mounted lever engageable by said detent member for maintaining said pin in a non firing position, means urging said lever t0 release said firing pin and acting in opposition to said detent member, pressure responsive means displaceable in response to variations in pressure, means operatively connecting said pressure responsive means to said detent member and adapted to move said detent member out of engagement With said lever when a predetermined altitude is attained, whereby said urging means pivots said lever to release said pin to a firing position, and altitude setting means operable for pivofing said detent member relative to said pressure responsive means -to preselect the altitude at which said detent member is moved out et engagement with said pivotally mounted lever.

10. A bornb fuze assembly adapted for functioning at a predetermined altitude, comprising a firing pin biased for movement to a firing position, a pivotally mounted lever normally positioned to black said pin from moving to a firing position, spring means associated With said lever for urging the latter to a pin releasing position, a pivoted detent member engageable with said lever and acting in opposition to said spring means for maintaining said lever in a pin blocking position, pressure sensitive means movable as a function of altitude change, engaging means mounted on said pressure sensitive means, said engaging means to contact said detent member to disengage the latter from the lever t0 release the firing pin when an predetermined pressure afiects said pressure sensitive means, and altitude setting means operatively associated with said detent member for varying the point et contact of said detent member with said engaging means to preset the altitude at which the fuze isto funotion.

References Cited in the file of this patent UNITED STATES PATENTS 1,228,748 Cooper June 5, 1917 1,364,008 Thoms0n Dec. 28, 1920 1,552,435 Johnson Sept. 8, 1925 1,850,196 Bardsley Mar. 22, 1932 1,916,244 Woodberry July 4, 1933 2,110,552 Hayden Mar. 8, 1938 2,420,237 Giroua rd May 6, 1947 2,438,853 Hebard Mar. 30, 1948 2,511,872 Parker June 20, 1950 2,586,861 Rabinow Feb. 26, 1952 FOREIGN PATENTS 7,735 Great Britain 1902 

